Balanced pressure rotor vane



June 5, 1962 R. M. NELDEN 3,037,459

BALANCED PRESSURE ROTOR VANE Filed Sept. 17, 1958 2 Sheets-Sheet 1fizz-=1.

BY 5/07 4 40/450, (.660/5 W /e45 June 5, 1962 Filed Sept. 17, 1958 R. M.NELDEN 3,037,459

BALANCED PRESSURE ROTOR VANE 2 Sheets-Sheet 2 INVENTOR. 2/6/7420 MNELOA/ nit States 3,037,459 BALANtIED PRESSURE RQTUR VANE Richard M.Nelden, Birmingham, Micln, assignor to American Radiator & StandardSanitary Corporation, New York, N.Y., a corporation of Delaware FiledSept. 17, 1958, Ser. No. 761,526

6 Claims. (Cl. 13--1l5) My invention relates to fluid couplings and moreparticularly to an improved coupling wherein the fluid energizing vanesof the impeller, or the energy absorbing vanes of the turbine, or both,are provided with spaced apertures to reduce the differential ofpressure exerted on opposite sides of the vanes thereby reducingstresses exerted on the vanes.

In the operation of fluid couplings a fluid energizing impellerconnected to a driving member is associated with a turbine or runnerconnected to a driven member. The impeller and turbine members havevaned concave channels which cooperate to transfer torque from thedriving member to the driven member.

The vanes of the impeller force the fluid to rotate with the impellershell and energy is imparted to the fluid as it is thrown radiallyoutwardly by centrifugal force developed by rotation of the impeller.The shell of the impeller guides the circulating liquid and directs itto flow axially as it is leaving the impeller. Conversely the shell ofthe turbine or runner member guides the liquid and redirects it to flowradially inwardly. The circumferential circulation of the fluid impingesupon the vanes in the turbine whereupon energy is extracted from theliquid as it is forced to flow radially inwardly in the turbine orrunner. The liquid flowing radially inwardly in the turbine is againdeflected axially and is directed to flow into the impeller. The liquidis thus circulated between the impeller and turbine members, energybeing imparted to the liquid by the impeller and absorbed therefrom bythe turbine.

in the operation of fluid couplings the sides of the impeller vaneswhich impart energy to the circulating fluid are subjected to heavyfluid pressures and loadings, andthe reverse sides of the vanes aresubjected to low fluid pressures or are substantially unloaded and as aresult of this differential pressure relatively high stresses areexerted upon the vanes. The same is true of the turbine vanes throughwhich torque is absorbed from the circulating fluid and is transferredto the driven member. One side of the turbine vanes are thus heavilyloaded and the other side of the vanes are subjected to very light orsubstantially no loading. The impeller and turbine vanes are thusstressed as beams and in fluid couplings which transmit high horsepowerthe vanes are subjected to both high bending and centrifugal stresses.

In addition the vanes of fluid couplings are subjected to impact loadsor shock stresses as the vanes of the impeller move circumferentiallyrelative to the vanes of the turbine thereby slicing through a body ofliquid due to slippage in the coupling.

I have found that the bending loads and shock stresses exerted ,on theimpeller and turbine vanes of fluid couplings can be prevented fromexceeding predetermined safe values by providing apertures of calibratedsizes in the working faces of the vanes to reduce high fluid pressuresexerted on the working faces of the vanes. Vane stresses can thus bematerially reduced.

An object of my invention therefore resides in the provision of animproved method of forming fluid coupling vanes in such a manner thatthe maximum loading and the stresses to which the vanes are subjectedcan be prevented from exceeding predetermined safe limits.

A further object of my invention is to provide a fluid coupling havingvanes of improved design.

Another object of my invention resides in the provision of an improvedfluid coupling wherein the vanes of the impeller and turbine members areselectively aperturcd to function as check valves or pressure equalizingports to reduce the maximum fluid pressure to which the vanes aresubjected.

Still a further object of my invention is to provide an improved fluidcoupling wherein the vanes are apertured to reduce the pressure exertedon the Working side of the vanes thereby maintaining the maximum loadingto which the vanes are subjected within safe limits.

Another object of my invention resides in the provision of angularlyrelated apertures through the vanes of impeller or turbine members orboth, the angularity of the apertures functioning to control thequantity of liquid bypassed through the vanes in proportion to thepressure exerted within the fluid coupling.

A further object of my invention is to improve the efficiency ofoperation of fluid couplings by reducing cavitation within the fluidcircuit by progressively by passing through the vanes increasedquantities of fluid in proportion to increases in fluid pressure exertedon the working faces of the vanes.

Yet another object of my invention resides in the provision of animproved fluid coupling wherein selectively spaced vanes are providedwith apertures of graduated sizes to avoid the development in thecircuit of fluid pressures exceeding safe maximum values.

Other objects and advantages of my invention will be apparent from thefollowing description, considered in conjunction with the accompanyingdrawings submitted for purposes of illustration only and not intended todefine the scope of the invention, reference being had for that purposeto the subjoined claims.

In the drawings wherein similar reference characters refer to similarparts throughout the several views:

FIGURE 1 is a sectional view of a fluid coupling embodying my invention;

FIG. 2 is a perspective View of one of the vaned members of my improvedfluid coupling illustrating one desirable disposition of pressurerelieving apertures in the vanes thereof;

FIG. 3 is a fragmentary view similar to a portion of FIG. 2 illustratinga modified form of my invention;

FIG. 4 is a sectional view taken substantially on the line 4 4 of FIG. 3looking in the direction of the arrows, and illustrating the angulardisposition of the apertures illustrated in FIG. 3;

FIG. 5 is a view similar to FIG. 3 illustrating a further modified formof my invention; and

' FIGS. 6 and 7 are fragmentary views illustrating further modifiedforms of the invention.

Before explaining the present invention in detail, it is to beunderstood that the invention is not limited in its application to thedetails of construction and arrangement of parts illustrated in theaccompanying drawings, since the invention is capable of otherembodiments and of be ing practiced or carried out in various ways.Also, it is to be understood that the phraseology or terminologyemployed herein is for the purpose of description and not of limitation.

Referring now more particularly to FIG. 1 it will be observed that adriving shaft 10 is operably connected to drive an impeller or primaryrotor 12 secured thereto in any convenient manner as by hub 14 carriedby the impeller. The impeller 12 has a concave-shaped shell 16terminating in a radially extended flange 18. A turbine 20 has aconcave-shaped shell '22 positioned in confronting relation to theimpeller shell 16. The turbine 20 is con- 3 nected through a hub 24 witha driven shaft 26 aligned with the driving shaft 10.

Inner and outer casings 28 and 30 having radially outwardly extendedflanges are secured to the flange 18 of the impeller shell 16 by bolts32. Part of the stationary bearing housing 36 extends into the outercasing 30 and supports the inner turbine bearing 37. Tue inner casing 28is contoured to overlie the turbine shell 22 and has a close running fitwith respect to the bearing housing 36 to provide a substantially fluidtight joint therewith. Apertures 39 in the outer periphery of the casing28 are provided to permit the escape of liquid from the fluid circuit toa scoop tube chamber 41 between the casings 28 and 30. An adjustablypositioned scoop tube 43 extended into the chamber 41 is provided toestablish the desired degree of filling in the circuit, therebycontrolling the turbine output speed and torque.

The impeller and turbine shells 16 and 22 respectively are provided withradially extended vanes and 42 to impart energy to and absorb energyfrom the liquid circulating in the fluid circuit defined by the impellerand turbine members 12 and 20* respectively. The impeller and turbinevanes 40 and 42 are provided with confronting shroud members 44 and 46to guide the circulating liquid flowing from the impeller to the turbineand from the turbine back to the impeller.

It will be understood that the impeller and turbine members may beformed in any desired manner as by machining, Welding, casting orstamping, and that the vanes 40 and 42 may be formed integrally with theshells 16 and 22 or may be secured thereto in any desired manner. Alsoit will be apparent that the shroud members 44 and 46 may be employed toassist in guiding the fluid, or if desired they may be omitted if thedesign is properly modified.

As shown in the embodiment of my invention illustrated in FIG. 1 theimpeller and turbine vanes 40 and 42 have a plurality of spacedapertures 48 and 50 to permit the circulating liquid to flow through thevanes from the side of the vanes subjected to the liquid pressure inimparting energy to the liquid or absorbing energy therefrom to the backor non-pressurized side of the vanes to relieve the force exerted on thevanes by fluid pressure exerted by the circulating liquid on the workingface of the vanes. A suflicient number of apertures 48 and 50 in theimpeller and turbine vanes 49 and 42 of suitable size may be employed topermit a suflicient flow of liquid through the vanes to relieve orreduce the pressure on the working face of the respective vanes tomaintain the stresses imposed within desired safe limits therebypreventing the development of undesirable bending stresses.

FIG. 2 illustrates a desirable embodiment of my invention as applied toan impeller 12. It will be observed that a plurality of apertures 48 arepositioned in the vanes 40 adjacent the outer profile 52 of the impellershell 16. The apertures 48 may be of graduated sizes and may be presentin suflicient number to relieve excess fluid pressure exerted on theouter periphery of the impeller. It will be apparent that successivelyspaced impeller vanes 40 may have different patterns of apertures torelieve fluid pressure to a desired degree. For example a symmetricalgroup of vanes 40 may have a cluster of several apertures and anothersymmetrical group of vanes 40 may have a group of a different number ofapertures which may also be of different size, and groups of aperturesvarying in number and size may be employed in adjacently positionedvanes to break up vibrational stresses. The same is true with respect tothe vanes 42 of the turbine. It will also be apparent that the samegrouping and size of apertures may be formed in all of the vanes of theimpeller or turbine members, or both.

FIG. 3 illustrates my invention applied to the turbine 20. It will benoted that the turbine vanes 42 in this embodiment are provided withapertures 50 spaced along the vanes adjacent the juncture of the vaneswith the shell i 22. Apertures of graduated sizes may be employed andthe apertures may be more closely spaced relative to each other in theareas subjected to the highest pressures. This expedient may of coursebe resorted to with respect to both the impeller and turbine.

The apertures 48 and 50 may, as shown in FIG. 4 be slanted or inclinedopposite to the direction of movement of the liquid relative to thevanes as shown by the arrow 56 to retard or delay the flow of powertransmitting liquid therethrough until the pressure exerted on theworking faces of the vanes reaches a substantially predetermined value.The apertures 48 and 50 reduce the pressure loads and impact stressesexerted on the impeller or turbine vanes 40 and 42 respectively tomaintain the stresses within workable limits. When low or mediumpressures are exerted on the working faces of the vanes the forwardinclination of the apertures through the vanes retard or delay the flowof fluid through the vanes at slow speeds. As increasing pressures aredeveloped within the fluid circuit and exerted on the working faces ofthe vanes, fluid flows through the forwardly inclined apertures, and thedegree of flow is dependent in part on the pressures exerted. Where thisexpedient is resorted to, the fluid pressure exerted on the impeller andturbine vanes can be controlled by permitting the escape of fluidthrough the vane when fluid pressure reaches a predetermined value,thereby reducing the stresses to which the vanes are subjected.

The use of apertures through the vanes alters the natural frequency ofthe vanes to provide stronger impeller and turbine members which areless susceptible to vibrational stresses.

Referring to FIG. 5 it will be observed that apertures 50 of graduatedsizes may be formed in the turbine vanes 4-2 to maintain substantiallyconstant pressure over the entire working face of the turbine vanes 42.While this expedient reduces the pressure within the working circuit andtherefore changes the torque transmitting characteristics of the unit,it does prevent subjecting the vanes to undesirable stresses. Theimpeller vanes 40 may of course be similarly treated with apertures ofgraduated sizes spaced to maintain substantially uniform pressure overthe Working faces of the vanes. The use of apertures to relieve pressureduring certain phases of operation of the unit also functions to reducecavitation.

While my invention has been illustrated as applied to several types ofpressure relieving configurations, it will be apparent that it issusceptible to many changes, in the number of apertures employed, in thedisposition of the apertures in the areas of the vanes subjected topredeter mined pressures, and in their angularity through the vanes toprovide desired results.

It will also be apparent that instead of employing apertures extendingthrough the body sections of the vanes, notches 50 in the edges of thevanes 40 may be employed as shown in FIG. 6, or notches orcircumferentially extending grooves may be formed in the shell 16 asshown at 62 in FIG. 7 to permit by-passing a portion of the circulatingfluid to the opposite sides of the vanes to relieve excess pressures,thereby reducing the danger of subjecting the vanes to excess pressures.It will of course be apparent that these expedients can be resorted towith respect to the impeller or to the turbine members.

I claim:

1. In a fracture-resistant rotor for a fluid coupling, the rotor havingan annular shell of toroidal section with substantially flat vanesextending generally radially of the shell and having the plane surfacesthereof disposed generally axially with respect to the shell, each ofthe vanes being of generally semi-circular configuration and having afree, generally straight edge defining a generally radially disposedinlet edge portion and a generally radially disposed outlet edgeportion, the improvement of a multiplicity of apertures extendingthrough each of the vanes and formed as a pattern, and adjacent vaneshaving differcut aperture patterns, whereby fluid is enabled to flowthrough the vanes from the high pressure face to the low pressure facealong portions of the vanes subjected to highest pressures, reducingpressure imbalances and the magnitude of bending stresses and detuningthe vanes to break up vibrational stresses incurred while the rotor isrunning at speed and load conditions tending to put the vanes inresonant vibration.

2. The combination defined in claim 1 wherein the apertures have fluidinlets formed in the high pressure vane faces and fluid outlets formedin the low pressure vane faces, with said fluid outlets being spacednearer the outlet edge portions of the vanes than said aperture fluidinlets.

'3. In a fracture-resistant rotor for a fluid coupling, the rotor havingan annular shell or toroidal section with substantially flat vanesextending radially of the shell and having the plane surfaces thereofdisposed generally axially with respect to the shell, each of the vanesbeing of generally semi-circular configuration and having a free,generally straight edge defining a generally radially disposed inletedge portion and a generally radially disposed outlet edge portion, theimprovement of a multiplicity of apertures extending through each of thevanes and spaced around the curved peripheral portions of the vanesadjacent the shell, said apertures being formed as a generallysemi-circular pattern extending substantially from the radial inlet edgeportion of the vanes to substantially the radial outlet edge portionthereof, and the apertures within the pattern being different inadjacent vanes, whereby fluid is enabled to flow through the vanes fromthe high pressure face to the low pressure face along portions of thevanes subject to highest pressures, reducing pressure imbalances and themagnitude of bending stresses and detuning the vanes to break upvibrational stresses incurred while the rotor is running at speed andload conditions tending to put the vanes in resonant vibration.

4. The combination defined in claim 3 wherein the apertures have fluidinlets formed in the high pressure vane faces and fluid outlets formedin the low pressure vane faces with said fluid outlets spaced nearer theoutlet edge portion of the vanes than said aperture fluid inlets.

5. In a fracture-resistant rotor for a fluid coupling, the rotor havingan annular shell of toroidal section with substantially flat vanesextending generally radially of the shell and with the plane surfacesthereof disposed generally axially With respect to the shell, each ofthe vanes being of generally semi-circular configuration and having afree, generally straight edge defining a radially disposed inlet edgeportion and a generally radially disposed outlet edge portion, theimprovement of a multiplicity of apertures extending through the vanesand spaced over the vanes in a semi-annular pattern, said patternsextending from the inlet edge portions of the vanes to the outletportions thereof, and the apertures within the patterns being diflerentin adjacent vanes, whereby fluid is enabled to flow through the vanesfrom the high pressure face to the low pressure face along portions ofthe vanes subjected to highest pressures, reducing pressure imbalancesand the magnitude of bending stresses and detuning the vanes to break upvibrational stresses incurred while the rotor is running at speed andload conditions tending to put the vanes in resonant vibration.

6. The combination defined in claim 5 wherein the apertures have fluidinlets formed in the high pressure vane faces and fluid outlets formedin the low pressure vane faces, with said fluid outlets spaced nearerthe outlet edge portions of the vanes than said aperture fluid inlets.

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